1. Field of the Invention
This invention is related to leak indicators for pipeline valves and, in certain particular aspects, to such indicators that are easily seen visually especially by a person in a low altitude plane flying over a pipeline.
2. Description of Related Art
Cross country pipelines have flow control valves located periodically (e.g. every ten to fifteen miles) along the pipeline's length. The great majority of these valves are in remote locations where no electrical power is available. Many of these valves are subjected to extremes of heat, cold, snow, ice, and wind. Typically pipeline valves are checked for leakage by flying the pipeline and visually inspecting the valves from the air. There have been many prior art attempts to provide leak indicators to facilitate the detection of fluid leaks.
U.S. Pat. No. 5,656,766 discloses a leak detector for an underground drain tank. A flag is raised above ground to indicate a leak in the tank, but a considerable, and perhaps environmentally injurious, amount of leakage must occur to activate the leak detector. U.S. Pat. No. 4,787,772 discloses relatively complex tank leak detection system that has an auxiliary tank that collects fluid leaking from a main tank and a pump system for pumping the leaked fluid from the auxiliary tank to a surface tank for inspection. Another tank leak detection system as disclosed in U.S. Pat. No. 4,685,327 monitors a closed inner space between an outer jacket and a gasoline tank's exterior. The leak detector is in communication with the closed space to monitor for leakage through either the storage tank or jacket. Several different types of detectors are used, including liquid level detectors, pressure change detectors, gas or liquid analyzers, and electronic probes. The detector itself may be positioned within the sleeve for ready accessibility. The detector can be periodically checked or it can be electronically connected to a remote receiving station for continuous monitoring. In one aspect the detector has a detecting liquid which completely fills the closed space and extends into a standpipe and a sight glass associated with the standpipe allows for easy observation of the liquid. A leak in the inner tank causes a migration of detecting liquid into the tank or, less likely, gasoline into the closed space. A loss of liquid into the tank results in a drop of the level of liquid in the standpipe. Migration of gasoline into the closed space is also detected by observation. The detecting liquid can be dyed a contrasting color for easier observation.
U.S. Pat. No. 5,146,778 discloses apparatus for the detection of oil or water leakages having a housing with a plurality of openings. The housing has a sufficient volume to permit the expansion of an absorbent material placed within it. Additionally, the housing has a hollow rod extending from it. Running through the rod is a wire. One end of the wire extends into the housing and holds a weighted member. The other end of the wire is connected to a signalling device for signalling persons of the presence of the liquid sought to be detected. When an expandable absorbent material is placed in the housing and the material detects the presence of a particular liquid, the absorbent material expands. This expansion forces the weighted member to push the wire through the hollow rod so that the signalling device is activated. Underground leakages in oil and/or water tanks may also be detected and signalled to persons in the area. In one aspect the system has two parts that separate causing a hidden section, originally within the container, to be revealed. The hidden section may be vividly colored for easy and quick visual recognition by persons in the area. In one aspect, the hidden portion is an inner portion of the container and an upper part of the container, and a signal is revealed as the upper separating part of the container. Alternatively the container may be constructed so that the perforated inner section of the container rests on a surface, and the bottom part of the container is capable of serving as the visual signal.
U.S. Pat. No. 5,421,193 discloses a leak detector including a float having a number of magnets connected to the float. Electromagnetic coils are disposed along a length of the possible range of travel of the float within the leak detector. The coils, when energized, interact with the magnet making the float move-about and settle to a position representing its true equilibrium buoyancy. Optionally, the leak detector includes a self-calibration apparatus that provides a reference signal indicating the fixed position of the self-calibration apparatus, allowing the leak detector to compensate for offset errors.
U.S. Pat. No. 4,847,599 discloses a fluid leak detector has a body with a chamber provided with a fluid inlet and outlet. A valve is disposed between the inlet and outlet and the valve closure member is connected to a diaphragm. Fluid in the chamber applies pressure on the diaphragm and the detector includes means which allow the valve to be open at a pressure greater than a predetermined value and cause the valve to close at pressures below that value, which may be due to a fluid leak. The detector has a safety lock-off mechanism which locks the valve once it has closed and which must be reset to allow the valve to open when fluid pressure has been restored. The detector also provides a visual indication (e.g. a two-position handle) of fluid leaks. A fluid supply installation incorporating the fluid leak detector will shut down the fluid supply if a leak is detected.
U.S. Pat. No. 4,901,751 discloses a fluid control valve with leak detection and containment features for use in a fluid handling system incorporating one or more flow controlling devices each including: an actuator; a weir valve and associated valve housing; and a pair of spaced apart diaphragms, one of which serves as the closure member for the weir valve and the other providing a secondary seal defining the limits of a containment chamber for at once preventing contamination of the controlled fluid, protecting the actuating mechanism and allowing immediate detection of valve closure failure. A piston member disposed within the chamber is coupled to the two diaphragms, and a fluid detection device is disposed in communication with a sealed containment chamber formed between the two diaphragms. The system includes electronic control apparatus responsive to the detection device and is operative to instantaneously shut down the system in the event of a detected failures.
U.S. Pat. No. 3,398,761 discloses a valve leak detection system for a valve apparatus with a valve body having inlet and outlet openings adapted to be connected to associated piping, a valve member disposed within the body and movable between open and closed valving positions with respect to said openings, sealing apparatus or device generally surrounding each of said openings, there being a closed body space within the valve body surrounding the valve member, vent valve apparatus exterior of the body and in communication with the body space, the vent valve apparatus operable to vent the body space to the atmosphere, and indicator apparatus for indicating leakage into the body space past one of the seals. In one aspect the indicator apparatus is an electrical indicator at the remote station, a pressure operated switch located near the valve, the pressure operated switch having a fluid pressure connection with the space within the valve body, and electrical circuitry connecting the electrical switch wit the indicator at the remote station and also with a visual indicator.
U.S. Pat. Nos. 2,601,840 and 2,708,896 disclose leak indicating protective covers for pipe flanges and valves, the covers including material that changes color upon contact by leaking fluid.
There has long been a need, recognized by the present inventor, for a quick-response reliable leak indicator for pipeline valves, e.g. due to elastomer valve stem packing seal failure. There has long been a need for such an indicator, recognized by the present inventor, which is easily visible, particular by a person in a low flying plane over a pipeline. There has long been a need, recognized by the present inventor, for such an indicator that will also collect leaked fluid and prevent it from contaminating the environment adjacent the valve and the pipeline. There has long been a need, recognized by the present inventor, for such an indicator that is weatherproof and/or bulletproof.